Technical Field
Aspects of the embodiments relate to internet protocol networks, and more particularly to systems, modes, and methods for digital media transmission over internet protocol networks.
Background Art
Video distribution throughout a facility is often accomplished through an audiovisual distribution network. Audiovisual (AV) distribution networks are increasingly common installations in commercial and residential facilities. Components of an audiovisual distribution network are typically distributed throughout a facility and networked to allow video to be distributed from one or more AV sources to one or more video sinks. For example, a corporate audiovisual distribution network may comprise multiple AV sources such as media servers, personal computer devices, disc players such as digital video disc (DVD) player and Blu-ray disc players and cable boxes distributed throughout a corporate campus. Audio sinks can include televisions, displays, projectors, video cassette recorders (VCRs), digital versatile disk (DVD) recorders, computers, digital video records, and other types of display/storage/play-back devices.
Internet Protocol (IP) is a communication protocol that can be employed to transmit video throughout the audiovisual distribution network. An IP protocol audiovisual distribution network may be implemented as a local area network (LAN), a wide area network (WAN), global area network (GAN), or various combinations thereon.
In a LAN, a group of devices are connected together in a localized area to communicate with one another and share resources. Ethernet, the most widely employed LAN technology, is specified in Institute of Electrical and Electronics Engineers (IEEE) 802.3 standard. Other LAN networking technologies can include, for example, Token Ring, and fiber distributed data interface (FDDI).
A WAN is a network that covers a broad area using private or public network transports. For example, any telecommunications network that links across metropolitan, regional or national boundaries is considered a WAN. It is common for the physical layer of these kinds of networks to be implemented with category (CAT) cable, coaxial cable, optical fiber or wireless transmission media. A WAN can include two or more LANs.
A GAN refers to a networks comprised of several or more different interconnected networks that cover an unlimited geographical area. Those of skill in the art have sometimes referred to the internet as a GAN.
Traditionally, to network several devices in a LAN, network equipment such as a network switch is required. A network switch is a computer networking device that links network segments or network devices by forwarding data from one device to another. In the past, network switches and the physical interconnections between devices had limited capacity and therefore the networks had limited bandwidth. Bandwidth limits may limit the amount or type of video distributed on an IP network. In addition, there may be applications where it is desirable to provide content or digital copy protection, such as high bandwidth digital content protection (HDCP), when transmitting over IP networks.
In consideration of the above, and taking into account the demands users have made on networks to provide streaming audio video products, improvements in audio distribution are needed. Among these developments are: 10 Gbit copper Ethernet transmission is becoming commonplace; the broadcast industry has embraced video and audio over IP, and finally HDMI 1.4 is being replaced by HDMI 2.0, which is designed to have a top speed of about 18 Giga pixels per second (Gpps) to support 4 k resolution at up to 60 Hz (refresh rate). Accordingly, an improved system for distributing video and audio that can accommodate such speeds and developments, and especially for switching between audio/video sources at said rates, is desired.
Furthermore, it is known that consumer A/V source components have the ability to output various audio formats. The type of audio format output by the source component depends on the source content, and the source itself. That is, some source components might only be able to output the audio in the format that it was created with, and which is stored in the source component. For example, one type of audio source component might be able to store audio data file 1 that is in surround sound 5.1, and it can only output audio data file 1 with the audio in surround sound 5.1. Further, there are source components that when connected directly to a sink, are capable of outputting the audio data file in an audio format that is compatible with the directly-connected sink capabilities. Suppose that the first device mentioned can change the format of the audio that is stored in audio data file 1; if the source recognizes the player as being capable of only using stereo audio, then the first source device can output the audio data file 1 in stereo, so that the sink connected to it can play it.
The problem of incompatible audio format devices is compounded when dealing with sources and sinks that connected over networks, and in particular Ethernet networks. While there are various distribution systems that can convert these audio (and video) formats to Ethernet compatible network formats, a problem occurs it is necessary or desired to distribute from one source to multiple sinks, each of which can have different capabilities. It is known that the majority of consumer source devices can only output a single audio format at a time. If a user want to use this content in multiple rooms (i.e., on multiple different sinks) the user is forced to use an audio format that is compatible with the equipment in all the devices that might use this content (i.e., at the lowest common format, which is generally stereo). That means a room that has high bit rate surround sound capabilities (e.g., Dolby Atmos, for example) will be limited to receiving stereo from the source device because the same content is also being used on a television in another room, which in this example can only play audio files in stereo. In other words, the lowest capable audio format takes precedent, and the audio that is output from a source with a higher or better capability will be degraded as a result. FIG. 10 illustrates a chart of the most common audio formats currently available, in alphabetical order. Those of skill in the art can appreciate that the list of the most common audio formats does not reflect an order of actual or perceived quality; that is, while many of skill in the art can agree that a surround 7.1 audio system generally sounds better than, for example, a simple stereo or mono audio signal, to some extent there is a level of subjectiveness to the “quality” of the different audio formats. But, what can be objectively measured is the bit rate, or bandwidth requirements that the different audio formats shown in FIG. 10 entail.
Accordingly, there is a need for an audiovisual distribution network that efficiently utilizes IP communication protocol and incorporates a system and method for transporting a plurality of audio formats to satisfy different capabilities at different users of the audio files.